h3
{
    text-align: center;
}

div
{
    text-align: center;

    width: 60%;

    margin-left: auto;

    margin-right: auto;
}

body
{
    text-align: center;
}

#grad1
{
    height: 100px;
    background: -webkit-linear-gradient(0deg, #43fff7, blue); /* Safari 5.1 - 6.0 */
    background: -o-linear-gradient(0deg, red, blue); /* Opera 11.1 - 12.0 */
    background: -moz-linear-gradient(0deg, red, blue); /* Firefox 3.6 - 15 */
    background: linear-gradient(0deg, red, blue); /* 标准的语法（必须放在最后） */
}

#grad2
{
    height: 100px;
    background: -webkit-linear-gradient(90deg, red, #37ff3c, #276fd2, blue); /* Safari 5.1 - 6.0 */
    background: -o-linear-gradient(90deg, red, #37ff3c, #276fd2, blue); /* Opera 11.1 - 12.0 */
    background: -moz-linear-gradient(90deg, red, #37ff3c, #276fd2, blue); /* Firefox 3.6 - 15 */
    background: linear-gradient(90deg, red, #37ff3c, #276fd2, blue); /* 标准的语法（必须放在最后） */
}

/**
不平均渐变
 */
#grad3
{
    height: 100px;
    background: -webkit-linear-gradient(180deg, red 20%, #37ff3c 30%, #276fd2 10%, blue 40%); /* Safari 5.1 - 6.0 */
    background: -o-linear-gradient(180deg, red 20%, #37ff3c 30%, #276fd2 10%, blue 40%); /* Opera 11.1 - 12.0 */
    background: -moz-linear-gradient(180deg, red 20%, #37ff3c 30%, #276fd2 10%, blue 40%); /* Firefox 3.6 - 15 */
    background: linear-gradient(180deg, red 20%, #37ff3c 30%, #276fd2 10%, blue 40%); /* 标准的语法（必须放在最后） */
}

#grad4
{
    height: 100px;
    background: -webkit-linear-gradient(-90deg, red, blue); /* Safari 5.1 - 6.0 */
    background: -o-linear-gradient(-90deg, red, blue); /* Opera 11.1 - 12.0 */
    background: -moz-linear-gradient(-90deg, red, blue); /* Firefox 3.6 - 15 */
    background: linear-gradient(-90deg, red, blue); /* 标准的语法（必须放在最后） */
}

#grad5 {
    height: 200px;
    background: -webkit-linear-gradient(left, rgba(255,0,0,0), rgba(255,0,0,1)); /* Safari 5.1 - 6.0 */
    background: -o-linear-gradient(right, rgba(255,0,0,0), rgba(255,0,0,1)); /* Opera 11.1 - 12.0 */
    background: -moz-linear-gradient(right, rgba(255,0,0,0), rgba(255,0,0,1)); /* Firefox 3.6 - 15 */
    background: linear-gradient(to right, #6ca3ff, #6855ff); /* 标准的语法（必须放在最后） */
}